In
computer networking,
upstream refers to the direction in which data can be transferred from the
client to the
server (
uploading). This differs greatly from
downstream not only in theory and usage, but also in that upstream speeds are usually at a premium. Whereas downstream speed is important to the average home user for purposes of
downloading content, uploads are used mainly for
web server applications and similar processes where the
sending of data is critical. Upstream speeds are also important to users of
peer-to-peer software.